When a supersonic or hypersonic flow in ducts which could be a flow plug. nozzle or combustion heat release, interacts with downstream blockage devices, a multiple shock wave system is produced as the result of shock wave and duct wall boundary layer interactions. A multiple shock wave system is called as "psendo-shock wave" or "shock train". The study of multiple shock wave and turbulent boundary layer interaction (MSW-TBLI) has important implications for the desigli and operation of scramjet engine/combustor-isolators and supersonic diffusers.In this project, the internal structure and turbulence phenomena of multiple shock wave/ turbulent boundary layer interactions (MSW-TBLI) in a rectangular duct were investigated.First, the internal structure of the MSW-TBLI was observed using schlieren photographs. laser holo-graphic interferograms and surface oil flow pictures. It was found that the boundary layer thickness increases at the leading oblique shock of the bifurcated first shock and decreases behind the trailing shock of the first shock, and that in the low confinenient case, the boundary layer separates under the bifurcated first shock, and in the high confinemeut. case the separation region of the boundary layer becomes small.Next, the time-mean and fluctuating velocities in the MSW-TBLI were measured in detail using the LDV.Spatial distributions of the turbulence intensity. Reynolds shear stress. and turbulence kinetic energy are presented. It was found that the tubulence intensity. Reynolds shear stress and turbulence kinetic energy in the boundary layer of the MSW-TBLI increases under the bifurcated first shock(4) 擬似衝撃波の上流域、発生領域、及び下流域における乱流境界層の乱流特性、すなわち流れ方向及び流れに垂直方向の乱れ強さ、レイノルズせん断応力、乱流エネルギ-分布等を、LDVによる詳細な測定により明らかにした。